New Tests Cast Doubts on ZigBee, 15.4

(Mar 22, 2007)
WLAN INTERFERENCE CASTS DOUBTS ON ZIGBEE, 15.4

Recent findings from an independent European manufacturing group have confirmed existing doubts about the viability of wireless control products based on IEEE 802.1.5.4, such as those from the ZigBee community, within the framework of typical residential wireless local area networks (WLAN).  

The findings, which were published in a recent white paper, showed substantial and frequently debilitating levels of signal interference between devices based on so-called "15.4" and typical residential WLAN technologies, such as IEEE 802.11 (Wi-Fi) and all its variants.  The measurements clearly demonstrated that control products using 15.4 technology are seriously compromised and often inoperable even within the most basic residential WLAN.  

Real World Conditions Are Too Much For ZigBee

Triggered in part by earlier reports of interference problems, comprehensive simulations of WLAN interference against ZigBee and other 15.4 based devices were conducted by employees of leading 15.4 and ZigBee chip vendors last year, and published as part of the IEEE802.15.4-2006 version of the specification. Despite clear evidence of harmful interference levels, these findings went largely unnoticed, overshadowed by the marketing efforts of the ZigBee community.

By contrast, WLAN interference tests in Europe were conducted by an independent OEM manufacturer under conditions that closely resemble typical European and US residential and commercial en?'Al9Ưn1~9Ё&G!085c(KzL2/,4-XK>I3,ih>fFT3o51T* 4= R+ iQa[C0Eݠ3֙j78i* ljD(zliN{.^?~._*[O~TJQ YA< gNeZ& (#+ WZl`H5]oS4!K[[Aat=:A|3zr%ZI = 0\}G;^M9*g?Q^FlP;;y|Q g Q=ّF%)dJ*t_Gg_ ՗u Д>s.4xbIYEƟj RF > 90)I "yzqSA*W3<+e8q۝7`-,0d^ YlmO=HaѢ - Zkrք$%]~PB|08X:+IPnRh{!h2Mt=2GM#3ĥm+ 6uYU-/d@~=XCT!#s9$[LI_xe'ig-jj$2_hlRZ78K E'[(T~G߀ 7Pg>:!q43k1(j9 s۽.k/Ha=c!7fsGɀ\6:OgWU.P'x*e̻@z|:SE t FJ `UV5-VCb/(m<-Bn 2C>~`|%gxTlb :%^TnVy\.<u+cN&/) Ht%F':x^6BK2$9Wy$J:G<\FN+,>KS AGL%/8 z> _8&ԅ 1~T5v2xv'C<&^Jh"_2X!+(2i5]4J&DyB#{qN qNk=~l{ҭ>*x-yG&jh7~c!(뷄 5؏ȮiO#!Bn6DbFU;'%#f;B+v6>|)4=L MxhA!7 <0g.;+18rגz' t2^=&ҀV8aH"T6q @,Cgf#ar\yAxYL>f;"9y-jYhV=6>T(,5GMwUolr%;)$qF# E<KvXCHe RqF^AvMspRe=[z^sy2k]0F%>d"lH:PqRV<[ӧE`fKR#6a!g8 s^eqgnt`cok_Ă4UM,y[_F>C% p2mD~&}],6U}_ ? {$E(:d!<=5 2Vŝg8RI#i.pBQ7+Ғq|FzavACj#KhF|{q.}P 3'hn"uӾ9:BdN|4ĺU~$ @!B$F*V#iKlUװ)1S icW[AF-,ծZ@U9$0Pr!'̥͊ m9 7o}R6l* JҋX,)*9$?'jaY9lwy#Eɇ>1$ϫ߂h+H^xEqY|Xxh"jr,'egXp7[ GӆvZo"ZFIb >gBP $l WWn-YXzQu$@蘍- p #kp)Z]j W ?ۀyw 2$X ? P31$bR=WM6p^US& Wng)"]`/,%'h('G}4c{cPHEseSz ,?G yhqP˙yYJLF+ Oe ~~'^8㡒PAOk }N)ᧂ )RZlE*Ȳ<^uez9beV1Y3I\$v3qM&p9MuS=:B,Y[N3#B2rw=!sK;9F}BR`0[7? ,jK_ZO!R"'f*-N29.80>YU6^D"Y] eg`Amv5ǓA a˝xȊeǰ}D B C]p*28o7q=`H5[P!~|]{j֊cd{Ԋ ޑŞɗ6 H5's><MrMui@EWʲ,K3 e; tB^}]`Us$M+\C?^8:^$ͱ`4. BC$!PM?Oj*D\mEff%p`/WH>c&A1Ѹ${%ޕ 08\d . *'qJ)_/af% c$8>.)')*zpd,WQRGGOi.`cGBk'8nVl<}eoRT\Fn/ ]/& SOqsfeHy3N*Fkk8ȮW |z\S^*(͕CC8GPq2 F{]?uY!ծjw@r׌L﹇mf œ2R|⢷"\yftìI)*F UYNKPhl.I;$DHW}P :W%Y+3;IxPy00fAvxT`-Kk=% XL n݇;)9ddJ41WYQ Vn2n:h>M -k;.byjR ;lR5?c8[P/2MAbEB6|^oz .w8(]esQ(L  v4Mw$Lϗ,"b[s*| a13; ӞgM/y(7 n2~$"Pw;Y,'-&|kCA:T>nk= Oed1^a;t|bwop'i v'D5T ;fu_<4' in a typical home WLAN will increase exponentially in the near-term future.  It is clear that 15.4-based control technologies attempting to co-exist within this framework will face even greater challenges regarding reliable or even achievable operation. 

Technologies that operate in frequency bands that are impervious to Wi-Fi interference are emerging as the obvious choice for control applications in today's wireless homes.  Due to a sub-1-GHz band design, Z-Wave technology has clear advantages that loom definitively in the wireless control space.

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Read the White Paper: WLAN Interference against IEEE 802.15.4
 
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